Organizations such as on-line retailers, cloud computing providers, Internet service providers, search providers, financial institutions, universities, and other computing-intensive organizations often conduct computer operations from large scale computing facilities. Such computing facilities house and accommodate a large amount of server, network, and computer equipment to process, store, and exchange data as needed to carry out an organization's operations. Typically, a computer room of a computing facility includes many server racks. Each server rack, in turn, includes many servers and associated computer equipment.
Because the computer room of a computing facility may contain a large number of servers, a large amount of electrical power may be required to operate the facility. In addition, the electrical power is distributed to a large number of locations spread throughout the computer room (e.g., many racks spaced from one another, and many servers in each rack). Usually, a facility receives a power feed at a relatively high voltage. This power feed is stepped down to a lower voltage (e.g., 110 volts). A network of cabling, bus bars, power connectors, and power distribution units, is used to deliver the power at the lower voltage to numerous specific components in the facility.
In some systems, an automatic transfer switch (“ATS”) device provides switching from a primary power system to a secondary (e.g., back-up) power system. In a typical system, the automatic transfer switch automatically switches the computing equipment to the secondary system upon detecting a fault in the primary power. Typical automatic transfer switches may switch from the primary power system to the secondary power system rapidly (e.g. switching may take approximately 12 milliseconds). However, there still may be a short period of time in which power is not being fed from an automatic transfer switch while it is switching from a primary power system to a secondary power system.
In some systems, components in a primary or secondary power system may generate harmonic currents or voltages. In power systems transmitting alternating current (AC) electrical power, the current varies sinusoidally at a specific frequency (e.g. 50 hertz or 60 hertz). Non-linear loads in a power system, such as rectifiers, may draw a current that is non-sinusoidal. This non-sinusoidal current draw may alter the current waveform so that the waveform includes additional frequencies other than the primary frequency (e.g. other than 50 hertz or 60 hertz). Also, upstream components in a power system, such as uninterruptible power supplies (UPS), may create harmonic voltages. For example, an upstream UPS that converts energy stored in a battery (as DC power) into AC current, may create harmonics because the conversion from DC to AC is approximate and varies from an ideal sine wave. In addition, harmonic currents may distort the voltage provided by a voltage source due to source impedance, resulting in harmonic voltages. Electrical equipment, such as computing equipment, receiving electrical power that includes harmonic currents or harmonic voltages may dissipate the harmonic currents or voltages before using the electrical power. Dissipating the harmonic currents or voltages may result in heating of the electrical equipment and may otherwise affect the reliability of the electrical equipment.
In some systems, changes in upstream equipment, such as energizing a transformer, may result in current or voltage surges. Other phenomena, such as lightning strikes or abrupt changes in a system load, may cause current or voltage surges. These current or voltage surges may damage downstream equipment, such as computer equipment. Some data centers, may include surge protectors in upstream components, such as upstream UPSs, to protect downstream equipment from current or voltage surges.
In some systems, upstream components may supply electrical power to a large number of downstream components. A failure in an upstream component, such as a UPS or power distribution unit (PDU), may affect a large number of downstream components, such as a large number of computer systems.
In some systems, current or voltage filtering, surge protection, reserve power storage, waveform monitoring, initiation of backup generators, and power monitoring may be performed by various separate devices spread out throughout a data center. In some systems, redundant devices or services may perform the same functions. Incompatibilities between devices or a lack of communication between devices may result in capabilities of devices not being fully utilized. In some systems, individual devices may be supplied by separate suppliers with separate standards, interfaces, requirements, etc. In some systems, non-commodity components may be required so that separate devices from different suppliers operate with each other.
While embodiments are described herein by way of example for several embodiments and illustrative drawings, those skilled in the art will recognize that embodiments are not limited to the embodiments or drawings described. It should be understood, that the drawings and detailed description thereto are not intended to limit embodiments to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to.